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We show that iridium complexes incorporating a tetrazolate ligand can be used as new highly phosphorescent emitters in the fabrication of high-efficiency organic light emitting devices (OLEDs). The nature of the excited states of these Ir(iii) complexes was probed by means of electrochemical analysis, absorption and photoluminescence spectroscopies and with the aid of TD-DFT calculations. To demonstrate the high stability of these classes of complexes we used TGA and DSC characterizations. These complexes are used as dopant emitters in the emissive layers. The as-fabricated OLEDs display high-efficiency and high-brightness with blue, green and yellow/orange emission.

Two kinds of low-band gap polymers, poly[{N-(1-octyldecyl)-2,7-carbazole)}-alt-{3,6-bis(phenylene-1,4-diyl)-2,5-di(1-octyldecyl)-2,5-dihydropyrrolo[3,4]pyrrole-1,4-dione}], poly(Cvz-PhDPP) and poly[{N-(1-octyldecyl)-2,7-carbazole)}-alt-{3,6-bis(pyridinyl-5-yl)-2,5-di(1-octyldecyl)-2,5-dihydropyrrolo[3,4]pyrrole-1,4-dione}], poly(Cvz-PyDPP), were synthesized by palladium-catalyzed Suzuki polymerization. Bulk heterojunction solar cells with an ITO/PEDOT/polymer:PC71BM/LiF/Al configuration were fabricated, which shows open-circuit voltage, short-circuit current density, fill factor, and power conversion efficiency of 0.76 V, 4.01 mA/cm2, 0.35, and 1.07% under AM 1.5 irradiation (100 mW/cm2), respectively.

The inversion-related molecules of the title compound, C26H21F2NO, associate into closed dimeric subunits via co-operative C—H...π interactions. Two non-classical C—H...O and one C—H...N intramolecular hydrogen bonds are also found in the crystal structure. The piperidin-4-one ring adopts a sofa conforamtion with the 1-benzyl group in the equatorial position, and the equiplanar fluorophenyl substituents in the 3- and 5-positions stretched out on either side. The 1-benzyl group is disposed towards the substituent in the 6th position of the piperidin-4-one ring. The 3,5-diene units possess E configurations.

In the title compound, C26H23NO, C—H...O hydrogen bonds generate a ribbon structure along the a axis. These ribbons further assemble into a one-dimensional sheet parallel to the ac plane via C—H...π interactions. The piperidin-4-one ring adopts a sofa conformation with the 1-benzyl group in the equatorial position, and the 3- and 5-phenyl substituents stretched out on either side. The benzylidene units adopt E configurations and the 1-benzyl group is disposed towards the 3- substituent of the piperidin-4-one ring.

The fluorinated and non-fluorinated dibenzylidene-4-piperidones were synthesized and their structures examined using X-ray crystallography. Interestingly, the para-fluorosubstituted dibenzylidene compound, in contrast to other analogs, is characterized by C–H...F bonded one-dimensional packing motif. To evaluate the ability of hydrogen bond donors and acceptors for forming interactions, in general and competitive situation, we have defined statistical descriptors. Analysis of Cambridge Structural Database using these newly defined parameters reveals high propensity of C–H...F interactions in organic crystals. The present structural study suggests much larger role of fluorine driven intermolecular interactions that are even though weak, but possess significant ability to direct and alter the packing.